ASA 127th Meeting M.I.T. 1994 June 6-10

5aSP1. Speech perception by normal children.

Susan Nittrouer

Boys Town Natl. Res. Hospital, 555 N. 30th St., Omaha, NE 68131

Since the pioneering work of Eimas et al. [Science 171, 319--324],
numerous experiments have shown that infants discriminate speech-relevant
acoustic parameters in the same way adults do. Both infants and adults
discriminate an acoustic difference if it places two stimuli on opposite sides
of a phoneme boundary, but fail to discriminate a difference if it places two
stimuli within the same phoneme category. Such results have led to the
suggestion that the relation between acoustic and phonemic structure is
innately recognized. However, studies of phoneme identification with preschool
and young school-aged children call into question the intransigent nature of
this proposed, innate mechanism. When two acoustic parameters are varied across
stimuli, the contributions of each to phonemic decisions appear to differ for
adults and children. Such results have led to the suggestion that the weights
assigned to various acoustic properties of the speech signal are retuned as
children gain experience with their native language, a proposal called the
developmental weighting shift. Evidence for this proposal will be presented, as
well as a discussion of its potential relation to developmental changes in
auditory capacities and phonemic awareness.